Effect of aging on microstructure of Mg-Zn-Er alloys

The effect of aging on microstructure of Mg-Zn-Er alloys at 473 K was investigated using hardness measurement, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that both Mg3.8Zn1.5Er and Mg5Zn2.0Er alloys exhibited visible age-hardening effect, especially the latter alloy. Microstructure analysis showed that, after being aged, lots of fine MgZn2 phases with hexagonal structure were found in the α-Mg matrix. Comparing with Mg3.8Zn1.5Er alloy, the accelerated hardening response of Mg5Zn2.0Er should be contributed to the increase in the content of Zn and Er elements.